Project Summary My long-term goal is to obtain a tenure track position at an accredited academic institution where I will perform independent research at the interface between virology and innate immunology. I envision developing a research program that utilizes novel approaches to investigate mechanisms of antiviral immunity at barrier surfaces, such as those of the skin, gut, lung, and oral mucosa. Obtaining the NIH pathway to independence K99/R00 award will provide me with the additional training I need to succeed as an independent investigator. In this proposal, I outline a training plan that encompasses formal coursework, participation in career development courses and workshops, and scientific collaboration with advisory committee members. The skills that I will acquire during the mentored phase of the award will make me uniquely qualified to answer important questions related to the host response to viral infection. The scientific goal of this study is to understand how non-hematopoietic cells contribute to antiviral immunity at barrier surfaces. Barrier surfaces are primary routes of entry for diverse viruses, and the initial antiviral responses elicited at these sites can have marked effects on viral spread within an infected host. Many viruses that infect barrier surfaces initially replicate within epithelial cells. However, the antiviral responses induced by these cells and their roles in preventing viral spread from the primary site of infection are poorly understood. Studies of antiviral immunity in epithelial cells have predominately focused on the role of interferons (IFNs). Yet, many viruses encode proteins that block IFN expression. Therefore, I propose that cells have alternative mechanisms to communicate infection and restrict virus replication during encounters with viruses that block IFN expression. This proposal is founded on my observation that viruses that inhibit IFN expression promote the release of interleukin (IL)-1 cytokines from infected epithelial cells, and that IL-1 cytokines elicit an antiviral state in human fibroblasts. I hypothesize that epithelial cells infected with IFN- evading viruses release preformed IL-1 cytokines to induce an antiviral response in neighboring non- hematopoietic cells. In addition, I propose that local IL-1R signaling in barrier tissues plays an important role in controlling virus spread from the initial site of infection. In this proposal, I will explore key aspects of this model of antiviral immunity.! Specifically, I will determine the genetic and biochemical basis for the mechanism of IL-1 cytokine release from virus-infected epithelial cells (Aim 1), determine the mechanisms by which a critical regulator of IL-1 cytokine induced antiviral responses, the transcription factor IRF1, is activated or inhibited (Aim 2), and define the antiviral mechanism(s) of non-hematopoietic cell IL-1 receptor (IL-1R) signaling in human skin (Aim 3). The results of these studies will provide important insight into the earliest encounters between host and virus, and will ultimately set the framework for my successful career as an independent investigator.